1. Field of the Invention
The present invention relates to ink compositions possessing excellent good stability. More particularly, the present invention relates to ink compositions for use in ink jet recording printers.
2. Background Art
Ink jet recording is a method wherein ink is ejected as droplets through fine nozzles to record letters or figures onto the surface of recording media. Ink jet recording systems which have been developed and put to practical use include: a method wherein an electric signal is converted to a mechanical signal using an electrostrictive element to intermittently eject ink reservoired in a nozzle head section, thereby recording letters or symbols on the surface of a recording medium; and a method wherein ink, reservoired in a nozzle head section, in its portion very close to the ejection portion is rapidly heated to create a bubble and the ink is intermittently ejected by volume expansion created by the bubble to record letters or symbols on the surface of a recording medium.
Various properties are required of inks used in the above ink jet recording. For instance, the good drying property of the print, no feathering in prints, uniform printing on the surface of various recording media, and, in the case of multi-color printing, no color-to-color intermixing are required.
Studies have hitherto been made on the addition of an ingredient, which accelerates the penetration of an ink composition into the record, to the ink composition to fast dry the ink composition on recording paper or to prevent mixing of adjacent different color inks.
For example, Japanese Patent Laid-Open No. 14260/1990 describes the use of lower alcohols as an ingredient for accelerating the penetration of ink.
Japanese Patent Laid-Open No. 55975/1982 describes that the addition of a surfactant to an ink composition lowers the surface tension of ink and can improve the penetration of ink.
Japanese Patent Laid-Open No. 157698/1995 describes a 1,2-alkanediol as a penetrating agent. However, all inks, which are specifically disclosed in this publication, contain a dye as a colorant.